Abstract
In the post-transient stage of a 1-Torr pulsed argon discharge, a computationally assisted diagnostic technique is demonstrated for either inferring the electron energy distribution function (EEDF) if the metastable-atom density is known (i.e., measured) or quantitatively determining the metastable-atom density if the EEDF is known. This technique, which can be extended to be applicable to the initial and transient stages of the discharge, is based on the sensitivity of both emission line ratio values to metastable-atom density, on the EEDF, and on correlating the measurements of metastable-atom density, electron density, reduced electric field, and the ratio of emission line pairs (420.1–419.8 nm or 420.1–425.9 nm) for a given expression of the EEDF, as evidenced by the quantitative agreement between the observed emission line ratio and the predicted emission line ratio. Temporal measurement of electron density, metastable-atom density, and reduced electric field are then used to infer the transient behavior of the excitation rates describing electron-atom collision-induced excitation in the pulsed positive column. The changing nature of the EEDF, as it starts off being Druyvesteyn and becomes more Maxwellian later with the increasing electron density, is key to interpreting the correlation and explaining the temporal behavior of the emission line ratio in all stages of the discharge. Similar inferences of electron density and reduced electric field based on readily available diagnostic signatures may also be afforded by this model.
Highlights
Experiments and testing facilities can be used in combination with theory, modeling, and simulation to decipher, relate, quantify, and predict in nature the mechanisms that are operating and the processes that are occurring
Either emission line pair is treated as an ingredient in a computationally assisted argon emission line ratio technique aimed at inferring electron energy distribution and at determining other plasma parameters in pulsed low-temperature plasma
The qualitative behavior of the emission line ratio indicates the direct correlation predicted in Section 2, that is, the ratio should be constant 9 and only increase in the enhanced presence of a population of electrons in the 13–20 eV range, which could occur as the electron density and temperature begins to stabilize approximately 10 μs into the could occur as the electron density and temperature begins to stabilize approximately 10 μs into the discharge
Summary
Experiments and testing facilities can be used in combination with theory, modeling, and simulation to decipher, relate, quantify, and predict in nature the mechanisms that are operating and the processes that are occurring. The technique described here represents a computationally assisted argon emission line ratio technique to infer electron energy distribution and determine other plasma parameters in pulsed low-temperature plasma. Replacing the 420.1/419.8 emission line ratio with another emission line ratio that does not require a high-resolution spectroscopic measurement represents an economical alternative for the plasma scientist. Either emission line pair is treated as an ingredient in a computationally assisted argon emission line ratio technique aimed at inferring electron energy distribution and at determining other plasma parameters in pulsed low-temperature plasma. 419.8 nm emission line with the 425.9 nm emission line to quantify direct electron-impact from the ground state, while continuing to use 420.1 nm emission as a measure of metastable density in the plasma [9]. Wavelengths referenced in this paper (name them by wavelength) were observed with those in agreement
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
